Abstract
Pecan (Carya illinoinensis) is an important woody tree species because of the high content of healthy oil in its nut. Thus far, the pathways and key genes related to oil biosynthesis in developing pecan seeds remain largely unclear. Our analyses revealed that mature pecan embryo accumulated more than 80% oil, in which 90% was unsaturated fatty acids with abundant oleic acid. RNA sequencing generated 84,643 unigenes in three cDNA libraries prepared from pecan embryos collected at 105, 120, and 165 days after flowering (DAF). We identified 153 unigenes associated with lipid biosynthesis, including 107 unigenes for fatty acid biosynthesis, 34 for triacylglycerol biosynthesis, 7 for oil bodies, and 5 for transcription factors involved in oil synthesis. The genes associated with fatty acid synthesis were the most abundantly expressed genes at 120 DAF. Additionally, the biosynthesis of oil began to increase while crude fat contents increased from 16.61 to 74.45% (165 DAF). We identified four SAD, two FAD2, one FAD6, two FAD7, and two FAD8 unigenes responsible for unsaturated fatty acid biosynthesis. However, FAD3 homologues were not detected. Consequently, we inferred that the linolenic acid in developing pecan embryos is generated by FAD7 and FAD8 in plastids rather than FAD3 in endoplasmic reticula. During pecan embryo development, different unigenes are expressed for plastidial and cytosolic glycolysis. Plastidial glycolysis is more relevant to lipid synthesis than cytosolic glycolysis. The 18 most important genes associated with lipid biosynthesis were evaluated in five stages of developing embryos using quantitative PCR (qPCR). The qPCR data were well consistent with their expression in transcriptomic analyses. Our data would be important for the metabolic engineering of pecans to increase oil contents and modify fatty acid composition.
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Claims 13
Claim · model-written summary
Mature pecan embryos contained more than 80% oil.
- Taxon
- pecan
_1_(24790682337).jpg?width=60)
Carya illinoinensise0 - Organ / stage
- mature pecan embryoe0
- Outcome
- oile0
- Value
- more than 80%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_1_(24790682337).jpg?width=500)
Verbatim
e0“mature pecan embryo accumulated more than 80% oil”
Claim · model-written summary
Unsaturated fatty acids comprised 90% of mature pecan embryo oil.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- unsaturated fatty acidse0
- Value
- 90%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in which 90% was unsaturated fatty acids with abundant oleic acid”
t0“Pecan”
Claim · model-written summary
Oleic acid was abundant in mature pecan embryo oil.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- oleic acide0
- Direction
- abundante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“unsaturated fatty acids with abundant oleic acid”
t0“Pecan”
Claim · model-written summary
Pecan embryo RNA sequencing generated 84,643 unigenes.
- Taxon
- pecanCarya illinoinensise0
- Organ / stage
- pecan embryose0
- Outcome
- unigenese0
- Value
- 84,643e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RNA sequencing generated 84,643 unigenes in three cDNA libraries prepared from pecan embryos”
Claim · model-written summary
The study identified 153 lipid-biosynthesis-associated unigenes.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- unigenes associated with lipid biosynthesise0
- Value
- 153e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified 153 unigenes associated with lipid biosynthesis”
t0“Pecan”
Claim · model-written summary
Fatty acid synthesis genes were most abundantly expressed at 120 DAF.
- Taxon
- pecanCarya illinoinensist0
- Gene
- genes associated with fatty acid synthesise0
- Outcome
- expressed genese0
- Direction
- most abundantlye0
- Value
- 120 DAFe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The genes associated with fatty acid synthesis were the most abundantly expressed genes at 120 DAF”
t0“Pecan”
Claim · model-written summary
Pecan embryo crude fat rose from 16.61 to 74.45% by 165 DAF.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- crude fat contentse0
- Direction
- increasede0
- Value
- 16.61 to 74.45%e0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“crude fat contents increased from 16.61 to 74.45% (165 DAF)”
t0“Pecan”
Claim · model-written summary
SAD, FAD2, FAD6, FAD7 and FAD8 unigenes were identified for unsaturated-fatty-acid biosynthesis.
- Taxon
- pecanCarya illinoinensist0
- Gene
- SAD, two FAD2, one FAD6, two FAD7, and two FAD8e0
- Outcome
- unsaturated fatty acid biosynthesise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“We identified four SAD, two FAD2, one FAD6, two FAD7, and two FAD8 unigenes responsible for unsaturated fatty acid biosynthesis”
t0“Pecan”
Claim · model-written summary
FAD3 homologues were not detected.
- Taxon
- pecanCarya illinoinensist0
- Gene
- FAD3e0
- Outcome
- FAD3 homologuese0
- Direction
- not detectede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“FAD3 homologues were not detected”
t0“Pecan”
Claim · model-written summary
The authors inferred FAD7 and FAD8 in plastids generate embryo linolenic acid.
- Taxon
- pecanCarya illinoinensise0
- Organ / stage
- developing pecan embryose0
- Gene
- FAD7 and FAD8e0
- Outcome
- linolenic acide0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“linolenic acid in developing pecan embryos is generated by FAD7 and FAD8 in plastids rather than FAD3 in endoplasmic reticula”
Claim · model-written summary
Different unigenes were expressed in plastidial and cytosolic glycolysis during embryo development.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- unigenese0
- Direction
- differente0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“different unigenes are expressed for plastidial and cytosolic glycolysis”
t0“Pecan”
Claim · model-written summary
Plastidial glycolysis was more relevant to lipid synthesis than cytosolic glycolysis.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- lipid synthesise0
- Direction
- more relevante0
- Comparator
- cytosolic glycolysise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plastidial glycolysis is more relevant to lipid synthesis than cytosolic glycolysis”
t0“Pecan”
Claim · model-written summary
qPCR results agreed with transcriptomic expression analysis.
- Taxon
- pecanCarya illinoinensist0
- Outcome
- qPCR datae0
- Direction
- well consistente0
- Comparator
- their expression in transcriptomic analysese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The qPCR data were well consistent with their expression in transcriptomic analyses”
t0“Pecan”